html {
  background-color: black;
}
        
body {
  margin: 0;
  width: 100vw;
  height: 100vh;
  position: relative;
  overflow: hidden;
}

#game-canvas {
  display: block;
  margin: auto;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border: 1px #222 solid;
}